what you say is right ..the hitch can limit the tow capacity..my hitch is rated at 5000 lb but the ball is stamped 3500 lb ..as you have low ratio you will have no problem with the steepest ramp .....remember if you go near the water to extend the pipe on the evap canister so you cannot suck in water on the ramp.. wont cost $10...search my posts for this its entitled "Dont go near water until you have done this modification "